Brilliant, I think that you may have shed some light on this for me - my Vector2D and Sprite classes do not have a public clone() method

I think this may be the problem - I am getting a copy of the Ship class, but it retains a reference to the Vector2D and Sprite classes from the original.
Going to have a check to see if that's the case now. Will keep you posted.
Edit:Ok, thanks CaptainJester, that did the trick.
I've still got some weird bugs going on, but i think they're now a problem with my Sprite drawing code that i just cant find. Duplication is working fine though, as far as i can tell.
EditEdit:Got it. I had missed adding a new parent Entity reference to my rendering component. derp.
Thanks again all.